diff mbox series

[net-next,1/4] net: use an atomic_long_t for queue->trans_timeout

Message ID 20211117032924.1740327-2-eric.dumazet@gmail.com (mailing list archive)
State Accepted
Commit 8160fb43d55d26d64607fd32fe69185a5f5fe41f
Delegated to: Netdev Maintainers
Headers show
Series net: make dev_watchdog() less intrusive | expand

Checks

Context Check Description
netdev/tree_selection success Clearly marked for net-next
netdev/fixes_present success Fixes tag not required for -next series
netdev/subject_prefix success Link
netdev/cover_letter success Series has a cover letter
netdev/patch_count success Link
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 4757 this patch: 4757
netdev/cc_maintainers warning 5 maintainers not CCed: atenart@kernel.org jhs@mojatatu.com jiri@resnulli.us alexanderduyck@fb.com xiyou.wangcong@gmail.com
netdev/build_clang success Errors and warnings before: 863 this patch: 863
netdev/module_param success Was 0 now: 0
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 4914 this patch: 4914
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 28 lines checked
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

Commit Message

Eric Dumazet Nov. 17, 2021, 3:29 a.m. UTC 
From: Eric Dumazet <edumazet@google.com>

tx_timeout_show() assumed dev_watchdog() would stop all
the queues, to fetch queue->trans_timeout under protection
of the queue->_xmit_lock.

As we want to no longer disrupt transmits, we use an
atomic_long_t instead.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: david decotigny <david.decotigny@google.com>
---
 include/linux/netdevice.h | 2 +-
 net/core/net-sysfs.c      | 6 +-----
 net/sched/sch_generic.c   | 2 +-
 3 files changed, 3 insertions(+), 7 deletions(-)
diff mbox series

Patch

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 31a7e6b2768123021690a3dc8572c5e8cb0e0027..143ac02c7f1cc90cf6704574fb0012e1ba830c70 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -592,7 +592,7 @@  struct netdev_queue {
 	 * Number of TX timeouts for this queue
 	 * (/sys/class/net/DEV/Q/trans_timeout)
 	 */
-	unsigned long		trans_timeout;
+	atomic_long_t		trans_timeout;
 
 	/* Subordinate device that the queue has been assigned to */
 	struct net_device	*sb_dev;
diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c
index 9c01c642cf9ef384fe54e56243b102ef838d0a62..addbef5419fbb62ce83f5132ae21c9d2872e95f5 100644
--- a/net/core/net-sysfs.c
+++ b/net/core/net-sysfs.c
@@ -1201,11 +1201,7 @@  static const struct sysfs_ops netdev_queue_sysfs_ops = {
 
 static ssize_t tx_timeout_show(struct netdev_queue *queue, char *buf)
 {
-	unsigned long trans_timeout;
-
-	spin_lock_irq(&queue->_xmit_lock);
-	trans_timeout = queue->trans_timeout;
-	spin_unlock_irq(&queue->_xmit_lock);
+	unsigned long trans_timeout = atomic_long_read(&queue->trans_timeout);
 
 	return sprintf(buf, fmt_ulong, trans_timeout);
 }
diff --git a/net/sched/sch_generic.c b/net/sched/sch_generic.c
index 3b0f620958037eb46e395f172c2315fdd98be914..1b4328bd495d54d44a9d51b53c8e8bc18b9cc294 100644
--- a/net/sched/sch_generic.c
+++ b/net/sched/sch_generic.c
@@ -467,7 +467,7 @@  static void dev_watchdog(struct timer_list *t)
 				    time_after(jiffies, (trans_start +
 							 dev->watchdog_timeo))) {
 					some_queue_timedout = 1;
-					txq->trans_timeout++;
+					atomic_long_inc(&txq->trans_timeout);
 					break;
 				}
 			}